JP4422445B2 - Method of depositing a silicon dioxide layer on a substrate by atomic layer deposition - Google Patents

Description

  The present invention relates to an improved method for growing a silicon dioxide layer on a substrate in semiconductor manufacturing or the like using atomic layer deposition. The method of the present invention facilitates very precise control over the overall properties of a silicon dioxide layer applied to, for example, a gate oxide or dielectric layer. The method of the present invention is particularly effective in manufacturing gate spacers, gate oxides, silicide blocking layers, bit line spacers, interlevel dielectric layers, etch stop layers, and related end products or intermediate products in semiconductor manufacturing. It is.

  In the manufacture of semiconductor devices, a silicon dioxide layer is often formed on the substrate surface by conventional techniques such as chemical vapor deposition (CVD), low pressure CVD (CVD), or plasma enhanced CVD (PECVD). These approaches are recognized to provide good step coverage at relatively low temperatures. However, when the density of the semiconductor device is increased, the height of each element constituting the device is increased. As a result, problems arise due to increasing pattern density variations and corresponding decrease in uniformity.

One approach to these recognized problems, as taught in US Pat. No. 6,090,442 (hereinafter referred to as “Klaus' 442”), incorporated herein by reference. Is an atomic layer deposition (ALD) technique. However, Klaus' 442 is a major drawback of ALD technology in that for surface reactions to be completed, they are typically temperatures above 600K and reactions greater than 10 ⁹ L (where 1 L = 10 ⁻⁶ Torr sec). Teaches that irradiation of the substance is required. Such high temperature and high irradiation processes are undesirable for ultra thin film deposition for a variety of reasons including the difficulty of performing such processes.

  Claus' 442 teaches an improved approach to this problem. Klaus' 442 provides a method for growing atomic layer thin films on functionalized substrates at room temperature using catalytic binary reaction sequence chemistry. More specifically, according to the Claus' 442 patent, a two-step atomic layer deposition (ALD) is grown on an OH-terminated substrate using a two-catalyst-promoted “half-reaction” performed at room temperature. Can be used.

In certain embodiments, Claus' 442 uses SiCl ₄ as the “first molecular precursor” and pyridine as the catalyst. First, the substrate is functionalized with OH ⁻ as the “first functional group” using, for example, H ₂ O. Next, the functionalized substrate comprises a catalyst that is a Lewis base or a Lewis acid (eg, pyridine) and a first molecular precursor that includes a major element of the film to be grown and a second functional group (eg, SiCl ₄ ). Expose to. As shown in Claus' 442, in the first “half-reaction”, the catalyst reacts with the first functional group of the functionalized substrate; the first molecular precursor is then (activated by the catalyst). Reacting with the first functional group results in displacement of the catalyst and bonding between the first functional group of the substrate and the main element of the first molecular precursor. Together, these two reactions comprise a first “semi-reaction” and begin film formation with a second functional group that is designed to be placed across the surface of the film.

  At this point in the Claus' 442 process, excess first molecular precursors and by-products are removed from the reaction chamber and exposed to a partially reacted substrate and a second molecular precursor. The catalyst reacts to activate the second functional group exposed along the surface of the membrane, along with the second molecular precursor, the substitution of the second functional group, and the main of the first molecular precursor. To the element. The second molecular precursor reacts with the bond between the primary component of the first molecular precursor and the catalyst to effect catalyst replacement and deposition of the first functional group on the newly grown surface layer. Occurs, thereby completing the full growth / deposition cycle and returning the substrate surface to a functionalized state in preparation for the next cycle.

  The catalyst-assisted deposition process of the Klaus '442 patent represents a substantial advance in ALD technology and allows room temperature ALD, but the surface density and uniformity of thin films grown using Klaus' 442 technology It has been found that the quality and quality do not meet the standards required in the semiconductor industry. Endless advances to smaller microelectronic components require more precise control over the characteristics of semiconductor devices. Such precise control requires more uniform surface properties and pattern density. The new advances in ALD technology of the present invention produce thin films for semiconductor devices that have better surface density and more uniform surface characteristics than the prior art, resulting in significantly more precise control over the overall characteristics of the thin film layer. This makes it possible to manufacture a higher quality semiconductor device suitable for the current miniaturization.

The Claus' 442 patent states that “a strong amine base such as triethylamine ((C ₂ H ₅ ) ₃ N) is a salt such as triethylammonium chloride (NH + (C ₂ H ₅ ) ₃ Cl—) in the presence of chlorosilane. "It has been shown to form a compound." This salt harms the surface, and this salt grows, degrading the reaction efficiency (column 9, lines 24 to 28). Thus, Claus' 442 teaches away from the presence of triethylamine, a tertiary aliphatic amine, in ALD applications.

  Accordingly, an object of the present invention is to use atomic layer deposition (ALD) to grow a very uniform thin film having good surface density, extremely high purity, and surface characteristics controlled with high precision. Is to provide a method.

  Another object of the present invention is to provide an ALD method for forming a silicon dioxide layer on a semiconductor substrate using a silicon compound having at least two silicon atoms as one of the reactant materials.

  Still another object of the present invention is to provide an ALD method for forming a silicon dioxide layer on a semiconductor substrate using a tertiary aliphatic amine compound as a catalyst material.

  Yet another object of the present invention is to provide optimal temperature and pressure ranges for carrying out the method of the present invention.

  Yet another object of the present invention is to provide a reaction / purge process sequence, timing and techniques for performing such deposition cycles to increase the benefits of the method of the present invention.

  Yet another object of the present invention is to provide a method of curing a silicon dioxide film on a substrate by the method of the present invention.

  Yet another object of the present invention is the excellent deposition deposited along the surface of the substrate used in applications such as gate spacers, gate oxides, silicide blocking layers, bit line spacers, interlevel dielectric layers, etch stop layers, etc. And providing a semiconductor device comprising a substrate having a silicon dioxide layer having a high surface density, extremely high purity and uniformity.

Yet another object of the present invention is to use silicon dioxide on a semiconductor substrate using Si ₂ Cl ₆ as the first reactant, or using a tertiary aliphatic amine as a catalyst, or both. It is to provide a catalyst assisted ALD method for forming a layer.

  These and other objects and advantages of the present invention will be better understood by the following detailed description with reference to the drawings, as discussed below.

The present invention is an improved method of using catalytic assisted atomic layer deposition (ALD) to form silicon dioxide thin films having improved properties and purity on a semiconductor substrate. In one embodiment, a silicon compound having at least two silicon atoms such as, for example, Si ₂ Cl ₆ is used as the first reactant in the ALD process. In the second embodiment, for example, a tertiary aliphatic amine compound such as trimethylamine is used as a catalyst in the ALD process. In the third embodiment, in the ALD process, a silicon compound having at least two silicon atoms is used as a first reactant, and a tertiary aliphatic amine compound is used as a catalyst. Other embodiments of the present invention provide methods for curing deposited silicon dioxide thin films, establish optimal temperature and pressure conditions for performing the methods of the present invention, and other reactants / purges for the methods of the present invention. Describe the process sequence.

Table 1 below summarizes a comparison of the theoretical chemical reactions of the conventional high temperature ALD method, the catalyst assisted ALD of the Claus' 442 patent, and the three embodiments of the present invention.

Table 2 below summarizes the catalyst, first reactant, and second reactant corresponding to different embodiments of the present invention.

  FIG. 1 outlines multiple steps, processes, and sequential chemical reactions that are typically applied to the method of the present invention for forming a silicon dioxide thin film on a substrate by catalyst-enhanced atomic layer deposition (ALD). FIG.

Stage 110
A suitable functionalized substrate is placed in the reaction chamber.

Stage 120
The substrate is preheated until the temperature of the substrate reaches a temperature suitable for initiating the silicon dioxide ALD process, typically about 25 ° C-150 ° C.

Stage 130
A new silicon dioxide layer is formed on the substrate surface by ALD. The cycle is repeated until a desired thickness of silicon dioxide thin film is formed on the substrate. Stage 130 consists of sub-stages 132-138 described below.

Stage 132
A mixture of the first reactant and catalyst is supplied to the reaction chamber. The catalyst acts to lower the reaction activation energy of the first reactant on the substrate. As a result, the process temperature decreases to approximately room temperature or slightly above room temperature.
Upon supplying the first reactant, the process temperature in the chamber is typically about 25 ° C.-150 ° C., preferably about 90 ° C.-110 ° C. The process pressure in the chamber is typically about 0.1-100 torr, preferably 0.5-5 torr. An inert gas, such as argon (Ar), may be supplied to the chamber along with the first reactant and the catalyst.
The -OH reaction site H reacts with the halogen atom of the first reactant in the presence of the first base catalyst to form a halogen acid. The halogen acid is neutralized using a first base catalyst to produce a salt. At the same time, the Si atoms of the first reactant react with oxygen on the reaction sites on the substrate to form a chemisorbed layer of the first product.

Paragraph 134
Byproducts of the first reaction process (paragraph 132), such as salts, unreacted first reactants, etc. are removed.

Paragraph 136
A mixture of a second reactant (including O and H) and a second salt catalyst is supplied to the chamber to chemically react the chemisorbed layer of the first reactant with the second reactant.
Examples of the second reactant are H ₂ O, H ₂ O ₂ or ozone. In one embodiment, the second salt catalyst is the same as the first salt catalyst.
When supplying the second reactant to the reaction chamber, the temperature and pressure ranges in the chamber are typically about the same as the temperature and pressure ranges used in step 132.
At this stage, the O element of the second reactant reacts with Si chemisorbed on the substrate surface. In the presence of the second salt catalyst, the H element of the second reactant reacts with the halogen atom, thereby producing a halogen acid. The salt is then formed by neutralization between such a halogen acid and a salt catalyst.

Paragraph 138
The by-product of the second reaction stage (stage 136) is removed.

Paragraph 140
The reaction chamber is evacuated to remove deposition byproducts remaining in the chamber. Desirably, the stage is completed in about 90 seconds. During stage 140, no gas is supplied to the chamber.

Paragraph 150
The substrate of the SiO ₂ thin film along the surface is taken out from the chamber.

Paragraph 160
This step involves curing the newly deposited SiO ₂ film. There are three methods used to cure the silicon dioxide layer deposited according to the present invention.
1. Heat treatment: substantially inert gas (ie, inert to the substrate surface), for example, in the presence of nitrogen (N ₂ ), oxygen (O ₂ ), hydrogen (H ₂ ), argon (Ar), etc. The substrate is annealed at 300 ° C-900 ° C.
2. Plasma treatment: annealing the substrate at about 200 ° C.-700 ° C. in the presence of oxygen (O ₂ ) or hydrogen (H ₂ ).
3. Typically ozone (O3) treatment at about 25 ° C-700 ° C

Any of the three curing methods described above are used in situ using SiO ₂ thin films grown using the catalyst assisted ALD process according to the present invention. It has been found that the above curing methods 2 and 3 work particularly well.

ここで、ＸはＦ、Ｃｌ、Ｂｒ、Ｉのようなハロゲンである。好適な実施形態では、第１の反応物はＳｉ_２Ｘ_６、Ｓｉ_３Ｘ_８、Ｓｉ_４Ｘ_１０、及びＳｉ_３Ｘ_６（三角形）から成る群から選択する。本発明の実施形態では、第２の反応物は、Ｈ_２Ｏ、Ｈ_２Ｏ_２及びオゾンから成る群から選択された酸素（Ｏ）及び水素（Ｈ）成分を含む化合物である。 First Embodiment In the first embodiment of the present invention, Si ₂ Cl ₆ or a similar compound such as silicon halide (halide) having two or more silicon atoms is used as the first reactant. A compound containing oxygen and hydrogen as the second reactant, such as H ₂ O and / or H ₂ O ₂ ; a salt compound such as ammonia or amine as the catalyst; A silicon dioxide thin film is formed. In this embodiment of the invention, the first reactant is a silicon compound having at least two silicon atoms, such as Si ₂ X ₆ , Si ₃ X ₈ , Si ₄ X ₁₀ , and Si ₃ having the following structure: A silicon halide compound selected from the group consisting of X ₆ (triangles).

Here, X is a halogen such as F, Cl, Br, or I. In a preferred embodiment, the first reactant is selected from the group consisting of Si ₂ X ₆ , Si ₃ X ₈ , Si ₄ X ₁₀ , and Si ₃ X ₆ (triangle). In an embodiment of the invention, the second reactant is a compound comprising an oxygen (O) and hydrogen (H) component selected from the group consisting of H ₂ O, H ₂ O ₂ and ozone.

As illustrated in FIG. 2, in the first stage, the chemical adsorbed layer of the first reactant along the substrate surface is exposed by exposing the mixture of the first reactant and catalyst to the hydroxyl functionalized surface of the substrate. Form. The unreacted first reactant and by-products are then removed from the area of the substrate. In the next process step, as illustrated in FIG. 2, the chemisorbed layer of the first reactant reacts with the second compound in the presence of a salt compound as a catalyst. Here, the catalyst may be the same catalyst used in reacting the first reactant or a different salt compound catalyst. The unreacted second reactant and by-products of this second reaction stage are removed from the substrate region. The surface of the substrate newly containing the SiO ₂ monolayer returns to the hydroxyl functionalized state ready to begin a new ALD cycle.

The previous process is very similar to the catalyst-assisted ALD technique described in Claus' 442, but the selection of different reactants and catalysts has a dramatic and dramatic impact on the nature and quality of the thin film surface layer of the substrate. I found it to be present. One important difference is that Claus' 442 teaches the use of SiCl ₄ , ie, a silicon halide having one silicon atom, while the above-described embodiments of the present invention have at least two silicon atoms. A silicon halide, for example, Si ₂ Cl ₆ is used. It has been found in the present invention that this difference provides a significant improvement in growth rate. In particular, it was found that the SiCl ₄ monolayer has a large space between molecules. In the case of SiCl ₄ , Si atoms react with O—H sites on the substrate, and SiCl ₄ rotates when it forms a single bond with O. Due to the steric hindrance of Cl (which does not participate in the reaction), the next O—H site cannot react with other SiCl ₄ . On the other hand, a Si ₂ Cl ₆ monolayer can react with two Si atoms simultaneously, thereby improving the speed of the ALD process. Furthermore, the result is a denser packing of molecules along the surface, improving the quality of the silicon dioxide layer.

As described below, in FIGS. 3-6, the characteristics and performance of a single layer of SiO ₂ grown on a substrate using the hexachlorosilicon (HCD) of the present invention, and the tetrachlorosilicon (TCS) method of Claus' 442. And a SiO ₂ single layer grown using

For example, the graph of FIG. 3 was obtained at various process temperatures using the deposition rate of a SiO ₂ monolayer on a substrate using a conventional SiCl ₄ approach and the Si ₂ Cl ₆ technique of the present invention. The deposition rate is compared. FIG. 3 shows that at all process temperatures, the deposition rate using Si ₂ Cl ₆ (circles) is approximately twice the deposition rate using SiCl ₄ (squares).

FIG. 4 shows the “silicon richness” of a thin film layer grown on a substrate using conventional TCS (SiCl ₄ ) and the thin film grown on the substrate using HCD (Si ₂ Cl ₆ ) of the present invention. The “silicon richness” of Using Auger electron spectroscopy to measure atomic concentrations of Si and O on the substrate surface at various sputtering times, FIG. 4 shows that the ratio of Si to O using the TCS technique is 1: 1.95. On the other hand, the ratio of Si to O using HCD technology is 1: 1.84. In other words, the thin film SiO ₂ layer formed using the HCD approach is preferably “richer” in silicon.

FIG. 5A shows XPS data comparing the silicon bonded state of silicon in a SiO ₂ monolayer grown using the HCD inventive approach and the bonded state in a single layer grown using the conventional TCS method. . The bond state differences shown in the graph of FIG. 5A, together with the silicon “richness” differences shown by FIG. 4, were formed when the SiO ₂ monolayer was grown by the HCD method instead of the TCS method. It seems to be explained by different types of silicon bonds. As shown in Figure 5B, the TCS method, considered adjacent silicon atoms in the SiO ₂ single layer is bonded to each other only via the intermediate oxygen atom, and the other, with HCD method of the present invention, SiO ₂ single It is believed that this leads to the formation of at least a plurality of direct Si-Si bonds in the layer.

FIG. 6 compares the wet etching rate for the SiO ₂ thin film formed using the HCD method of the present invention with the wet etching rate for the SiO ₂ thin film formed using the conventional TCS method (the bar graph of FIG. 6). The vertical scale is discontinuous to carry both data). FIG. 6 shows that the wet etching rate of the SiO ₂ thin film formed using the HCD method of the present invention is about 6 times better than the SiO ₂ thin film formed using the TCS method.

Second Embodiment In the second embodiment of the present invention, a silicon halide is used as the first reactant; a second reactant containing oxygen and hydrogen atoms, for example, H ₂ O and / or H ₂ O ₂ ; A ternary fatty amine catalyst is used to produce a silicon dioxide film on the functionalized surface of the substrate. In this embodiment of the present invention, the chemisorbed layer of the first reactant is along the substrate surface by exposing the functionalized surface of the substrate to a mixture of the first reactant and catalyst in a first process step. Form. The unreacted first reactant and by-products are then removed from that region of the substrate. In the next process step, the chemisorbed layer of the first reactant reacts with the second reactant in the presence of the ternary fatty compound amine catalyst. This by-product of the second process stage is removed from the substrate area.

Embodiments of the present invention are novel in the use of tertiary aliphatic amines as reaction catalysts, in process efficiency, removal or minimization of unwanted by-products, and in the purity and quality of SiO ₂ thin films deposited on substrates. And there is a totally unexpected effect. More specifically, an amine having one nitrogen-hydrogen (N—H) bond, such as ammonia (NH ₃ ), one or two aliphatic amines (NR, H ₂ , or NR ₂ H) is used as a catalyst. If used, it has been found that there is a tendency to form unwanted by-products with silicon-nitrogen (Si-N) bonds, as shown in the following equations (1) and (2):
(1) SiCl ₄ + NR ₂ H → Cl ₃ Si—NR ₂ + HCl
(2) SiCl ₄ + NH ₃ → Cl ₃ Si—NH ₄ ⁺ Cl ⁻ (salt)
Here, R is an aliphatic group (C _x H _y ) having about 1 to 5 carbon atoms, and the aliphatic groups R may be the same or different.

However, it is a major cause of the formation of particles leading to surface layer impurities (eg, as shown on the right side of equations (1) and (2) above) and degrades the quality of the deposited SiO ₂ thin film. I understood it. In contrast, if a tertiary aliphatic amine having the general formula NR3 (wherein R is an aliphatic group having about 1 to 5 carbon atoms (C _x H _y )) is used as the reaction catalyst, It has been found that it does not substantially form special by-products with silicon-nitrogen (Si-N) bonds. As a result, the method of the present invention deposits a much higher purity SiO ₂ film with higher quality and better uniformity.

FIG. 7 and Table 3 discussed below demonstrate the validity and significant importance of this finding. FIG. 7 is the result of an RGA analysis confirming the formation of a solid byproduct when the ALD process is performed using an amine catalyst that is not a tertiary aliphatic amine. FIG. 7 shows the catalyst type taught in Claus' 442 using SiCl ₄ as the first reactant and catalyzed by dimethylamine ((H ₃ C) ₂ NH), ie, an amine having an N—H single bond. Based on ALD process. A residual mass spectrometer was coupled to the ALD reaction chamber for analyzing by-products from the reactants. The mass spectrum in FIG. 7 confirmed the formation of Cl ₃ Si—N (CH ₃ ) ₂ as an unwanted (unnecessary) byproduct of the reactant. Such by-product formation means that some of the Si from the SiCl ₄ first reactant was wasted in forming the by-product instead of depositing on the substrate surface as SiO ₂ .

Other evidence of the advantages of embodiments of the present invention over the prior art is shown in Table 3 below.

In Table 3, the desired (with a size of at least 0.16 μm) deposited on the substrate surface in the same region when catalytic ALD was performed using SiCl ₄ as the first reactant and a different amine as the catalyst. Not comparing the number of particles. Table 3, using a molecule with SiCl ₄ ie three N-H bond as ALD catalyst, ALD processes produce tens of thousands of products particles on the surface of the SiO ₂ thin film. This very high level of particle contamination on the SiO ₂ thin film adversely affects the performance of the semiconductor device and is totally unacceptable for many of the very demanding modern semiconductor applications.

Table 3 shows that the use of dimethylamine, a single susceptible N—H bond, as an ALD catalyst is effective in reducing particulate byproducts on the order of about an order of magnitude. So as to obtain with dimethyl amine catalyst, even at particle production in the range number 1000 of the SiO ₂ thin film is beyond the allowable range for the semiconductor device of very high performance. Table 3 shows a reduction of 3 orders of magnitude for ammonia and 2 orders of magnitude for dimethylamine by using trimethylamine as an ALD catalyst and removing all the NH bonds susceptible to attack by it. It reveals dramatic and unforeseen consequences of reducing by-product particle production to the order of several tens. ,

Another advantage of this embodiment of the present invention over the prior art is that this embodiment of the present invention uses a tertiary aliphatic amine catalyst instead of pyridine, which is a suitable catalyst in, for example, the Claus' 442 patent. is there. Pyridine is a heterocycle that has a chemical formula of C ₅ H ₅ N and contains a ring of 5 carbon atoms and 1 nitrogen atom. It exists at room temperature as a toxic liquid that has an irritating and characteristic odor and requires careful handling. When used as a catalyst in an ALD process, pyridine evaporates to a gaseous state (the boiling point of pyridine is 115.5 ° C.). Thus, the equipment for treating pyridine is complex and the pyridine supply line is easily contaminated.

  In contrast, low molecular weight tertiary aliphatic amines such as trimethylamine are easier to use than catalysts which are gaseous at ambient conditions and thereby tend to undergo phase changes at normal reaction conditions. Furthermore, the toxicity of trimethylamine is much lower than that of pyridine, and the boiling point of trimethylamine is 3-4 ° C.

Third Embodiment In the third preferred embodiment of the present invention, it is often impossible to realize all of the advantages and effects of the two previous embodiments of the present invention. In this embodiment, the first reactant comprises a silicon compound having at least two or more silicon atoms, ie a silicon halide such as Si ₂ Cl ₆ , and the second reactant comprises O and H atoms. A silicon dioxide thin film is grown on the functionalized surface of the substrate using compounds such as H ₂ O and / or H ₂ O ₂ and a tertiary aliphatic amine catalyst.

  In this embodiment of the present invention, the first reactant and the tertiary aliphatic amine catalyst are mixed in a first process stage to form a chemisorbed layer of the first reactant along the substrate surface. Expose the functionalized surface of the substrate. The unreacted first reactant and by-products are removed from the area of the substrate. In the next process step, the first reactant chemisorbed layer reacts with the second reactant in the presence of a tertiary aliphatic amine catalyst. This by-product of the second reaction stage is removed from the substrate region.

In another embodiment of the present invention, the use of a gas pulse / purge method for one or more of the plurality of process stages 132-138 of FIG. 1 improves the efficiency of the method of the present invention and improves process contamination. It was found that the nation can be removed and the quality of the SiO ₂ thin film formed on the substrate can be improved. FIG. 8 illustrates a gas pulse method for performing steps 132-138 of FIG. 1 as described below.

Stage 132
The first reactant and a suitable catalyst are flowed to the reaction chamber via each independent supply line. At this time, in order to avoid contamination from the mixed gas of the first reactant and the catalyst, an inert gas such as argon gas can be flowed into the chamber through the second reaction supply line.

Stage 134
An inert gas for purging is flowed into the chamber through the first reactant supply line, the second reactant supply line, and the catalyst supply line.

Step 136
A second reactant containing O and H atoms and a suitable catalyst are flowed into the chamber via each independent supply line. At this time, in order to purge the first reactant supply line, an inert gas such as argon gas can be flowed into the chamber via the first reactant supply line.

Stage 138
An inert gas for purging is flowed into the chamber through the first reactant supply line, the second reactant supply line, and the catalyst supply line.

A plurality of exemplary “recipes” for pulsing / evacuating or purging gas to various feed lines and reactant chambers over a 10 second process time interval, corresponding to steps 132-138 of FIG. Alternatively, the sequence is shown in FIGS. FIG. 9 shows a process purge sequence with the following steps in one cycle performed at selected process time intervals using an inert gas to purge and remove by-products: 0-2 second process time— HCD supply; 2-4 seconds process time - purge; 4-7.5 seconds process time -H ₂ O supply; 7.5-10 seconds process time - purge. FIG. 10 shows a process exhaust sequence in which the exhaust pressure is lower than the first and second reactant supply pressures with the following steps consecutive in one cycle: 0-2 seconds process time—HCD supply; 2-4 seconds process time - exhaust; 4-7.5 seconds process time -H ₂ O supply; 7.5-10 seconds process time - the exhaust. FIG. 11 shows a process purge-evacuation sequence in which exhaust is used after purging, with the following steps consecutive in one cycle: 0-2 second process time-HCD supply; 2-3 second process time-purge; -4 sec process time - exhaust; 4-7.5 seconds process time -H ₂ O supply; 7.5-8.5 seconds process time - purge: 8.5-10 seconds process time - the exhaust. FIG. 12 shows a process evacuation-purge sequence in which purge is used after evacuation, with the following steps consecutive in one cycle: 0-2 second process time-HCD supply; 2-3 seconds process time-evacuation; 3 -4-second process time-purge; 4-7.5 second process time-exhaust; 7.5-8.5 second process time-exhaust: 8.5-10 second process time-purge.

ｋ_ｄ：脱離速度
Ａ：アレニウス定数
Ｅ_ｄ：脱離活性エネルギー
Ｒ：気体定数
Ｔ：温度 In another embodiment of the present invention, the temperature condition for carrying out the catalytic assisted ALD to grow an SiO ₂ thin film on a substrate by the present invention is optimized by harmonizing the process parameters of two competing. On the other hand, as illustrated in FIG. 13, the deposition rate when forming SiO ₂ using a catalyst-assisted ALD and a compound having a plurality of silicon atoms (for example, Si ₂ Cl ₆ ) as the first reactant is Inversely proportional to temperature. FIG. 13 generally shows that the higher the process temperature, the lower the deposition rate. This appears to be due to the deposition rate, and since ALD is a surface reaction, it is a unique feature of the ALD process. The higher the process temperature, the higher the surface desorption activity energy of the atoms participating in the reaction. As a result, the “residence time” at the surface is reduced from the minimum time required for the reaction to take place according to the following equation:

k _d : Desorption rate A: Arrhenius constant E _d : Desorption activity energy R: Gas constant T: Temperature

  The higher the process temperature, the easier the dehydroxylation (dehydration oxidation) of the O—H chain on the substrate surface. Thus, the number of reaction sites along the surface is reduced and the deposition rate is reduced.

On the other hand, as shown in FIG. 14, in the SIMS (secondary ion mass spectrometer) graph of the change over time of the carbon content at three different process temperatures, the carbon content of the ALD deposited SiO ₂ thin film also depends on the process temperature. Change. Typically, at low process temperatures, carbon-containing byproducts of the ALD reaction process are not fully removed from the substrate surface during the process and are trapped in the deposited SiO ₂ film. The resulting increase in the impurity level of the thin film degrades the quality of the semiconductor device.

  Therefore, these two process parameters must be balanced with each other to optimize process temperature conditions. Based on the foregoing considerations, it has been found that in this embodiment of the invention, the optimum process temperature range is about 90 ° C-110 ° C.

In another embodiment of the present invention, the pressure conditions for performing catalyst assisted ALD to grow a SiO ₂ thin film on a substrate according to the present invention are optimized by matching two competing process parameters. On the other hand, as illustrated in FIG. 15, the deposition rate when forming SiO ₂ using catalyst-assisted ALD is inversely proportional to the pressure. That is, the higher the pressure, the thicker the SiO ₂ film deposited over a predetermined time interval / ALD cycle number.

On the other hand, FIG. 16 shows that a non-linear relationship exists between the process pressure and the non-uniformity (sex) of the SiO ₂ thin film. Thus, FIG. 16 up to a point reduces the non-uniformity of the deposited layer with higher process pressure; however, beyond this point, higher pressure correlates with higher non-uniformity.

  Therefore, these process parameters must be balanced with each other in order to optimize process pressure conditions. Based on the above considerations, the optimum process pressure range was determined to be in the range of about 50 mm Torr to about 5 Torr in accordance with embodiments of the present invention.

Without departing from the scope of the invention described herein, for use in high-performance semiconductor device, the above-mentioned improved catalysts assist ALD formation of the SiO ₂ thin film on the substrate surface, yet other modifications and variations It will be apparent to those skilled in the art that all matters contained in the above detailed description are illustrative only and should not be construed in a limiting sense.

FIG. 3 is a flow diagram schematically illustrating the steps of the ALD method of the present invention for forming a silicon dioxide thin film on a substrate. FIG. 3 outlines the multiple chemical reaction steps on which the improved ALD method of the present invention is based. It is the graph which compared the deposition rate (rate) of the silicon dioxide on the board | substrate in the ALD method of this invention, and that of the conventional ALD process. It is the graph which compared the "richness" of the silicon dioxide thin film of the silicon dioxide thin film formed on the board | substrate using the ALD method of this invention, and that of the conventional ALD process. It is the graph which compared the state of the silicon bond of the silicon | silicone in the silicon dioxide single layer formed on the board | substrate using the ALD method of this invention, and that of the conventional ALD process. FIG. 5B is a schematic illustration of different silicon chemical bond arrangements that illustrate the differences in bonding states established in FIG. 5A. It is the graph which compared the wet etching rate of the silicon dioxide thin film formed using the ALD method of this invention, and that of the conventional ALD process. FIG. 5 is a chromatograph showing the formation of unwanted special by-products with Si—N bonds when performing an ALD process according to the teaching of the prior art using a catalyst containing one or more N—H bonds. FIG. 5 illustrates a gas purge method for supplying reactants and catalysts to a reactant chamber according to one embodiment of the present invention. FIG. 4 shows a possible representative “recipe” or sequence cycle for gas purge / pumping and / or purging used in carrying out the ALD method of the present invention. FIG. 6 illustrates another possible exemplary “recipe” or sequence cycle for gas purge / pumping and / or purging used in carrying out the ALD method of the present invention. FIG. 6 illustrates another possible exemplary “recipe” or sequence cycle for gas purge / pumping and / or purging used in carrying out the ALD method of the present invention. FIG. 6 illustrates another possible exemplary “recipe” or sequence cycle for gas purge / pumping and / or purging used in carrying out the ALD method of the present invention. The deposition rate of the SiO ₂ onto the substrate using an ALD method of the present invention is a diagram showing how changes how according to the process temperature. FIG. 3 shows how the impurity content (measured by the carbon present) of SiO ₂ formed using the ALD method of the present invention varies according to the process temperature. The deposition rate of the SiO ₂ onto the substrate using an ALD method of the present invention is a diagram showing how changes how according to the process pressure. Non-uniformity of the ALD method SiO ₂ thin film was formed using the present invention is a diagram showing how changes how according to the process pressure.

Claims (33)

A method of forming a silicon dioxide layer on a substrate surface of a semiconductor product using a catalyst assisted atomic layer deposition process, wherein the functionalized surface of the substrate is a first mixture comprising a first reactant and a first catalyst. And then exposing the surface to a second mixture of a second reactant and a second catalyst to form a silicon dioxide monolayer on the substrate surface. In the method
From step (a) to step ( b ):
(A) using a first reactant comprising at least one element selected from the group consisting of silicon compounds having at least two silicon atoms, and a first catalyst selected from the group consisting of ammonia and amines. Stage;
(B) and the use of the first reactant comprising at least one member selected from the group consisting of silicon compounds having two silicon atoms even without low, selected from the group consisting of tertiary aliphatic amine compound Using a first catalyst comprising at least one element in combination;
Comprising at least one of
The second reactant is selected from the group consisting of H ₂ O, ozone and H ₂ O ₂ ;
The second catalyst is selected from the group consisting of ammonia and an amine;
The method comprises the steps of removing unreacted reactants, catalyst and reactant by-products from the substrate surface following each reaction step. The method of claim 1, wherein the first reactant comprises Si ₂ Cl ₆ . The first reactant is one selected from the group consisting of Si ₂ X ₆ , Si ₃ X ₈ , Si ₄ X ₁₀ , and Si ₃ X ₆ (triangle), wherein X is a halogen group element. Item 2. The method according to Item 1. 2. The first catalyst comprises a tertiary aliphatic amine compound of the general formula NR ₃ wherein each R is the same or different aliphatic group having 1 to 5 carbon atoms. The method described in 1.   The method of claim 1, wherein the first catalyst comprises trimethylamine. The method of claim 1, wherein the first reactant comprises Si ₂ Cl ₆ and the first catalyst comprises trimethylamine. The method according to claim 1, wherein the method is performed in a temperature range of 90 ° C to 110 ° C. The method of claim 1, wherein the method is performed in a pressure range of 0.5 to 5 torr.   The method of claim 1, wherein the first catalyst and the second catalyst are the same.   The method of claim 1, wherein the first reactant, the second reactant, and the catalyst are supplied to the substrate surface from independent supply lines. The following deposition cycles: (a) the period during which the first reactant and catalyst are supplied to the substrate surface via their respective supply lines along with the inert gas supplied from the second reactant supply line. (B) the supply of the first reactant and the catalyst is stopped, and instead the inert gas is supplied to the first reactant supply line, the second reactant supply line, and the catalyst supply line. A first purge time which is a period of time being fed via; (c) a second reactant and catalyst with their inert gas fed from the first reactant feed line through their respective feed lines A second reaction time which is a period during which the substrate is supplied to the substrate surface; (d) the supply of the second reactant and catalyst is stopped, and instead an inert gas is supplied to the first reactant supply line and the second Supplied through the reactant supply line and catalyst supply line The method of claim 1 0 comprising a cycle; second purge time is that period.   The method of claim 1, comprising the step of repeating the deposition cycle multiple times on the same substrate to obtain a desired thickness of the silicon dioxide thin film. Desired film to obtain a silicon dioxide thin film having a thickness A method according to claim 1 1 comprising the step of repeating a plurality of times deposition cycles on the same substrate.   The method of claim 1, comprising curing the deposited silicon dioxide layer. Said curing step is the following:
_(A) in the presence of _{N 2, O 2, H 2} , and an inert gas selected from the group consisting of Ar, heat treatment with the annealing the silicon dioxide layer at 3 00 ℃ -900 ℃;
(B) plasma treatment comprising annealing the silicon dioxide layer at 200 ° C.-700 ° C. in the presence of O ₂ or H ₂ ;
(C ) ozone treatment comprising exposing the silicon dioxide layer to O ₃ at 25 ° C.-700 ° C .;
The method of claim 1 4 are those selected from one of the. The following sequence:
Supplying the first reactant and the first catalyst to the region including the substrate for a process time length t ₁ : immediately after the time length t ₁ , the region is inactivated for a time length t ₂ step purging with gas: immediately after the time length t _2, during the duration t _3, step to evacuate the area in order to at least partially discharge the inert gas and other gaseous materials from the region: the time length t ₃ immediately after, during the time length t _4, the second reactant and a second catalyst comprising: a supply to the region of: immediately after the time length t _4, during the time length t _5, the region inert gas Purging with: each step according to a sequence of: immediately following time length t ₅ , evacuating the region to discharge at least partially inert gas and other gaseous substances from the region for a time length t ₆ : The method of claim 1 comprising a purge-evacuation process for atomic layer deposition. The following sequence:
Supplying the first reactant and the first catalyst to the region including the substrate for a process time length t ₁ : immediately after the time length t ₁ and at least partly from the region for a time length t ₂ stages to evacuate the area in order to discharge the gaseous substance: immediately after the time length t _2, during the duration t _3, step purging region with inert gas: immediately after the duration t _3, the time length between t _4, the second reactant and a second catalyst comprising: a supplied to the region: immediately after the length of time t _4, during the time length t _5, at least partially discharging the gaseous material from the area For each atomic layer deposition, a purge-evacuation process was provided according to the sequence: evacuating the region for: immediately following time length t ₅ and purging the region with inert gas for time length t ₆ The method of claim 1. (A) introducing a substrate into the chamber;
(B) supplying a first reactant, a catalyst and optionally an inert gas to the chamber, wherein the first reactant is a silicon halide compound having at least two silicon atoms; Is a stage selected from the group consisting of ammonia and amines;
(C) purging from the chamber the first reactant and catalyst that have not reacted with the reaction by-products;
(D) supplying a second reactant, catalyst, and optionally an inert gas, to the chamber, wherein the second reactant is a compound having an oxygen component, the catalyst comprising ammonia and an amine. A stage selected from the group consisting of;
(E) purging from the chamber the second reactant and catalyst that have not reacted with the reaction byproduct;
(F) repeating steps (a)-(e) until the silicon dioxide thin film has the desired thickness;
A method of forming a silicon dioxide thin film on a substrate surface comprising: The method of claim 18 , wherein the first reactant is Si ₂ Cl ₆ . Wherein the first reactant is selected from the group consisting of Si ₂ X ₆ , Si ₃ X ₈ , Si ₄ X ₁₀ , and Si ₃ X ₆ (triangle), wherein X is a halogen group element The method of claim 18 , wherein The method of claim 18 , wherein the second reactant is selected from the group consisting of H ₂ O, ozone, and H ₂ O ₂ . The process according to claim 18 , wherein the same catalyst is used in step (b) and step (d). The process according to claim 18 , wherein the catalyst used in step (b) and the catalyst used in step (d) are different compounds . The process according to claim 18 , wherein the catalyst is a tertiary aliphatic amine. Steps (b) to (e) are performed in the following sequence:
Supplying the first reactant and catalyst to the chamber for a process time length t ₁ ; purging the chamber with an inert gas for a time length t ₂ immediately after the time length t ₁ ; immediately after the time length t _2, during the duration t _3, step to evacuate the area in order to at least partially discharge the inert gas and other gaseous material from the chamber; immediately after the duration t _3, the time length between t _4, the second reactant and the catalyst comprising: a supplying to the chamber: immediately after the time length t _4, during the time length t _5, step purging the chamber with an inert gas: time length t ₅ the method of claim 1 8 carried out according to a sequence that: immediately after, during the time length t _6, the step of evacuating the space to at least partially discharge the inert gas and other gaseous material from the chamber of . Steps (b) to (e) are performed in the following sequence:
Supplying the first reactant and catalyst to the chamber for a process time length t ₁ ; immediately after the time length t ₁ , at least partially exhausting gaseous material from the chamber for a time length t ₂ Evacuating the chamber to perform; purging the chamber with inert gas immediately after time length t ₂ for a time length t ₃ ; immediately after time length t ₃ , for a time length t ₄ Supplying a second reactant and catalyst to the chamber; immediately after time length t ₄ , evacuating the chamber to at least partially exhaust gaseous material from the chamber for a time length t ₅ ; time The method of claim 18 , wherein the method is performed according to a sequence immediately after length t ₅ , purging the chamber with inert gas for a time length t ₆ . (A) introducing a substrate into the chamber;
(B) supplying a first reactant, catalyst and optionally an inert gas to the chamber, wherein the first reactant is selected from the group consisting of silicon compounds having at least two silicon atoms; Comprising at least one element , wherein the catalyst is a tertiary aliphatic amine;
(C) purging the first reactant and catalyst that have not reacted with the reaction by-products from the chamber;
(D) supplying a second reactant, catalyst, and optionally an inert gas, to the chamber, wherein the second reactant is a compound having an oxygen component, the catalyst comprising ammonia and an amine. A stage selected from the group consisting of;
(E) purging the chamber with a second reactant that has not reacted with reaction byproducts and the catalyst;
(F) repeating steps (a)-(e) until the silicon dioxide thin film has the desired thickness;
A method for forming a silicon dioxide thin film on a substrate surface comprising: The method according to claim 2 7 wherein the first reactant is _Si 2 Cl _6. Wherein the first reactant is selected from the group consisting of Si ₂ X ₆ , Si ₃ X ₈ , Si ₄ X ₁₀ , and Si ₃ X ₆ (triangle), wherein X is a halogen group element the method according to claim 2 7 is. The method according to claim 2 7 wherein the second reactant is one selected from the group consisting of between H _{2 O} and ozone and H ₂ O ₂ Prefecture. The method according to claim 2 7 using the same catalyst de phase and step (b) and (d). Steps (b) to (e) are performed in the following sequence:
Supplying the first reactant and catalyst to the chamber for a process time length t ₁ ; purging the chamber with an inert gas for a time length t ₂ immediately after the time length t ₁ ; immediately after the time length t _2, during the duration t _3, step to evacuate the area in order to at least partially discharge the inert gas and other gaseous material from the chamber; immediately after the duration t _3, time during the long t _4, the second reactant and the catalyst comprising: a supplying to the chamber: immediately after the time length t _4, during the time length t _5, step purging the chamber with an inert gas: the time length t _3. Immediately following _5, the operation is performed according to a sequence of: evacuating the region to at least partially evacuate the inert gas and other gaseous substances from the chamber for a time length t _6. 8. The method according to 7 . Steps (b) to (e) are performed in the following sequence:
Supplying the first reactant and catalyst to the chamber for a process time length t ₁ ; immediately after the time length t ₁ , at least partially exhausting gaseous material from the chamber for a time length t ₂ Evacuating the chamber to perform; purging the chamber with inert gas immediately after time length t ₂ for a time length t ₃ ; immediately after time length t ₃ , for a time length t ₄ Supplying a second reactant and catalyst to the chamber; immediately after time length t ₄ , evacuating the chamber to at least partially exhaust gaseous material from the chamber for a time length t ₅ ; time immediately after the length t _5, during the duration t _6, the step of purging the chamber with an inert gas: the method according to claim 2 7 having to be carried out according to the sequence of.

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